Recently, as the use of leather materials and the like has been increasing for a vehicle interior, physical properties and characteristics of a coating composition have been enhanced. In the vehicle interior, a soft feel coating having improved soft feel is mainly used for vehicle interior parts which a driver or a passenger may frequently contact. When the coating is applied, a coating film is formed by a 2-coat-1 bake coating. A primary coating is applied for adhesion and color, and then a secondary coating is applied to provide a smooth texture. Process cost and working hour increase by applying the coating and drying the primer coating, a color base coating composition and a top coat coating composition in order, and during this process, an amount of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) generated is increased compared to a 1-coat-1 baking oil acryl lacquer coating, which applies only the primary coating. Accordingly, an environment-friendly BTX-free 1-coat-1 bake coating, capable of improving both workability of the oil acryl lacquer coating composition and smooth surface of the coating, is needed.
For example, 1-coat-1 bake coating, which uses an oil acryl lacquer coating composition, has been applied. The 1-coat-1 bake coating has good physical properties, such as heat resistance, moisture resistance, adhesion and the like. However, the 1-coat-1 bake coating according to the related art has week scratch resistance, and does not provide smooth feeling when a driver of passenger contacts a coated film.
A high elastic coating composition applying a polyester polycarbonate mixture-based polyurethane resin has been used to improve scratch resistance of a coating film and protect the coated surface. The high elastic coating composition according to the related art provides aesthetic improvement and smooth and strengthen coated surface. However, since 2-coat-1 bake coating is applied, process cost, working hour, volatile organic compounds and hazardous air pollutants increase, compared to the oil acryl lacquer.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.